Animals can escape, bite, claw; plants, being rooted in one spot, have had to come up with a host of ingenious protective devices: spines and thorns that cause pain to those who would steal their fruits; insecticides; caffeine—whose purpose is not to keep humans awake but to ward off caterpillars; and chemicals that interfere with hormone-production in insects. Of course plants are not the only organisms to adapt; the hungry insects or birds or other animals that feed off the plant adapt to its devices, developing chemical antidotes, or camouflaging their appearance to confuse the plant, in extreme cases growing long necks like the giraffe’s to reach the precise leaves they need. Thus the struggle to survive continues. (28 minutes)